Why does a nightmare disappear as soon as one recollects the Buddha during it?

Question: Why does a nightmare disappear as soon as one recollects the Buddha while having it? 

Answer: When the mind consciousness recollects the Buddha in daily life, it perfumes the manas, so that the manas holds the Buddha in its mind and also understands the benefits of recollecting the Buddha. When encountering a dangerous situation in a dream, it directly raises the thought of the Buddha and utters the Buddha's name—the name comes out spontaneously, without the mind consciousness needing to deliberate and then decide to recollect the Buddha. This is true recollection of the Buddha (buddhānusmṛti), and it can resonate with the Buddha. Once the Buddha's power bestows blessing, the nightmare vanishes. Circumstances turn according to the mind: as soon as the mind of Buddha-recollection appears, the nightmare realm disappears, and the suffering transforms into peace and tranquility.